With the recent advent of high performance fighter aircraft capable of sustained high acceleration (9+G.sub.Z) and high altitude (+50,000 feet) flight, air crew protection performance has become a major limitation in aircraft operation. This is due to both current standard equipment design limitations and the lack of integration by design.
The provision of head protection and bodily restraint in conventional helmet configurations presents a major limitation in protection performance. With respect to state of the art helmet configurations, human factors such as comfort, stress and fatigue are performance limiting, principally because the entire head (eyes, ears, neck) is not protected. Additionally, in a high sustained (+G.sub.Z) acceleration environment, the weight of the head born helmet configuration compounds rather than ameliorates air crew G-loading induced difficulties. For example, conventional helmet configurations which include oxygen-communication masks may weigh up to 7 pounds. While the weight of such headborne components are of limited concern during low acceleration flight of an aircraft, they may have drastic effects on the pilot during high acceleration of the aircraft. The high G-forces imposed on the pilot effectively multiply the weight of the helmet and, therefore, increase the head and neck stress of the pilot during attempted head movements. It is therefore highly desirable to provide a helmet which is not burdensome to the pilot's head and neck during G-force acceleration, and which is easily rotatable to maximize visibility.
Conventional pilot restraint devices, such as lap or upper body straps, restrain the pilot's torso both in flight and during an ejection sequence. However, the pilot's neck and head are free to move forward, in a lateral direction, or rotate in order to achieve desired viewing positions. Also, conventional straps have been found to be inadequate in correctly positioning the pilot in the ejection seat during ejection. The correct position involves the pilot's head, neck, and spine being aligned along the axis of propulsion of the ejection seat from the aircraft. Injuries may occur to the pilot by contact with parts of the aircraft or simply as a result of the high acceleration of the ejection seat as it is propelled from the aircraft. It is therefore desirable to provide a restraining system which both allows freedom of movement of the upper body and head within the cockpit during normal flight and enhances alignment and restraint of the upper body and head of the pilot both in flight and during the ejection sequence.